The Lipid and Lipoprotein Biochemistry Core Laboratory will serve all projects on a highly interactive and collaborative basis. The primary role of this core unit is to provide phenotypic data on measures of plasma lipoproteins. This core unit also is responsible for processing and storing the blood samples used by the core unit and by Project 1. Quantitative measures of lipoprotein phenotypes will be made by clinical chemical and immunochemical techniques. Standard clinical chemical procedures will be used to quantify serum TC and HDL-C after precipitation. Immunoturbidimetric and other immunochemical techniques will be used to measure serum concentrations of apoAI, apoB, apoE, LP(A) particles bearing specific isoforms. In addition, we will determine apo(a) isoform phenotypes. The gradiant gel electrophoresis (GGE) technique, established in our laboratory for the specific purpose of genetic research involving large numbers of samples, will enable estimates of quantities of cholesterol in each of four size-resolved HDL particle classes: HDL1a, HDL1b HDL2, and HDL3. In addition, the GGE technique will be used to determine the distribution of cholesterol among four size-resolved LDL particle classes, as well as the median particle diameter and diameter of the predominant LDL species in each sample. Blood processing will involve isolating serum for phenotypic measures, processing it for storage as 60 mul aliquots, and storing clots as a backup source of DNA. Sera and clots will be catalogued in the computerized inventory database, maintained at -80 degrees Centigrade, and retrieved as needed. Blood from 750 patients and inbred progeny projected to undergo the dual dietary challenge will be processed and assayed for lipoprotein phenotypes on the occasions of the three dietary samplings. In addition, LP(a) phenotypes, apo(a) phenotypes, and LDL cholesterol distributions will be assayed on 1,800 samples from non-inbred animals that underwent the dual dietary challenge during the current project period.